Main Wastewater Research Articles

A Comprehensive Evaluation of Struvite Control at the EBMUD Main Wastewater Treatment Plant

A Comprehensive Evaluation of Struvite Control at the EBMUD Main Wastewater Treatment Plant

The interplay of institutions, actors and technologies in socio-technical systems — An analysis of transformations in the Australian urban water sector

Literature on socio-technical transitions has primarily emphasized the co-determination of institutions and technologies. In this paper, we want to focus on how actors play a mediating role between these two pillars of a socio-technical system. By introducing the theoretical concept of institutional work, we contribute to the conceptualization and empirical assessment of agency processes in socio-technical systems. We illustrate this approach by analyzing recent developments in the Australian urban water sector, where seawater desalination technology has experienced an unexpected, but rapid diffusion to all major cities, often interpreted as a reaction to a major multi-year drought. However, the drought broke and left all but one plant unused. This has led many commentators wonder how such a massive investment – which is likely to limit alternative development trajectories in the sector for the coming decades – could have happened so quickly and why other, potentially more sustainable technologies, have not been able to use the momentum of the crisis to break through. A comparative analysis between seawater desalination and its main rival wastewater recycling in regard to processes of institutional work provides valuable insight into how technology, actors and institutions mutually shaped each other.

Integrating the selection of PHA storing biomass and nitrogen removal via nitrite in the main wastewater treatment line

A novel scheme was developed for the treatment of municipal wastewater integrating nitritation/denitritation with the selection of polyhydroxyalkanoates (PHA) storing biomass under an aerobic/anoxic, feast/famine regime. The process took place in a sequencing batch reactor (SBR) and the subsequent PHA accumulation in a batch reactor. The carbon source added during the selection and accumulation steps consisted of fermentation liquid from the organic fraction of municipal solids waste (OFMSW FL) (Period I) and OFMSW and primary sludge fermentation liquid (Period II).Selection of PHA storing biomass was successful and denitritation was driven by internally stored PHA during the famine phase. Under optimum conditions of SBR operation ammonia removal was 93%, reaching a maximum nitrite removal of 98%. The treated effluent met the nitrogen limits, while PHA-storing biomass was successfully selected. The maximum accumulation of PHA was 10.6% (wt.) since the nutrients present in the carbon source promoted bacterial growth.

Bioenergy from stillage anaerobic digestion to enhance the energy balance ratio of ethanol production

The challenges associated with the availability of fossil fuels in the past decades intensified the search for alternative energy sources, based on an ever-increasing demand for energy. In this context, the application of anaerobic digestion (AD) as a core treatment technology in industrial plants should be highlighted, since this process combines the pollution control of wastewaters and the generation of bioenergy, based on the conversion of the organic fraction to biogas, a methane-rich gaseous mixture that may supply the energetic demands in industrial plants. In this context, this work aimed at assessing the energetic potential of AD applied to the treatment of stillage, the main wastewater from ethanol production, in an attempt to highlight the improvements in the energy balance ratio of ethanol by inserting the heating value of methane as a bioenergy source. At least 5–15% of the global energy consumption in the ethanol industry could be supplied by the energetic potential of stillage, regardless the feedstock (i.e. sugarcane, corn or cassava). The association between bagasse combustion and stillage anaerobic digestion in sugarcane-based distilleries could provide a bioenergy surplus of at least 130% of the total fossil fuel input into the ethanol plant, considering only the energy from methane. In terms of financial aspects, the economic gains could reach US$ 0.1901 and US$ 0.0512 per liter of produced ethanol, respectively for molasses- (Brazil) and corn-based (EUA) production chains. For large-scale (∼1000 m3EtOH per day) Brazilian molasses-based plants, an annual economic gain of up to US$ 70 million could be observed. Considering the association between anaerobic and aerobic digestion, for the scenarios analyzed, at least 25% of the energetic potential of stillage would be required to supply the energy consumption with aeration, however, more suitable effluents for agricultural application could be produced. The main conclusion from this work indicates that anaerobic processes should be considered the core technology to treat stillage, based mainly on the attractive relation energy generation-financial return and on the possibility to keep the advantages inherent to the common fertigation when using the treated effluent in agriculture.

INFLUENCE OF SOLID MOISTURE AND BED HEIGHT ON CULTIVATION OF Aspergillus niger FROM SUGARCANE BAGASSE WITH VINASSE

Solid-state cultivation (SSC) may be defined as growth of microorganisms on a solid support impregnated or not with a nutrient solution in near absence of free-water conditions. The use of sugarcane bagasse as a support for SSC usually demands that the particles are impregnated and moistened with nutrient solution. Vinasse is the main wastewater of ethanol fermentation-distillation. As there are no reports of the use of wastewater for moistening solid supports in SSC, the proposal is the development of an innovative process, with valuation of these by-products. Thus, the aim of this research was to evaluate SSC of Aspergillus niger using sugarcane bagasse and vinasse for citric acid production. The results indicate that citric acid production and glucose consumption are dependent on oxygen availability, which can be modulated by selection of bed height and air-flow in packed-bed bioreactors.

COD and nitrogen removal from sugarcane vinasse by heterotrophic green algae Desmodesmus sp.

Vinasse is the main wastewater from the ethanol fermentation–distillation process, generated in large volumes during industrial sugarcane processing. Desmodesmus is a green algae genus with recognized ability to treat wastewater containing organic matter and to consume nutrients under heterotrophic growth conditions. Thus, the aim of this research was to evaluate Desmodesmus sp. growth in sugarcane vinasse. Results indicated slight elevation of pH, low oxygen, and low carbon dioxide consumption. Nitrogen and chemical oxygen demand (COD) removal were 52.1 and 36.2%, respectively. Specific growth rate of 0.15 h−1 and high yield of COD to biomass at first hour (0.5 mg mg−1) suggest the feasibility of biomass production of this green algae in sugarcane vinasse.

Microbial-chemical indicator for anaerobic digester performance assessment in full-scale wastewater treatment plants for biogas production

Anaerobic digestion was introduced into wastewater treatment plants several years ago, but anaerobic digestion performance has not yet been achieved. The variability of the microbial community in digesters is poorly understood, and despite the crucial role of anaerobic digestion reactors, the microbial equilibrium that yields the best performance in these reactors has only recently been hypothesised. In this study, two full-scale continuous anaerobic reactors, placed in Torino’s main wastewater treatment plant in northern Italy, were followed to develop a summary indicator for measuring anaerobic digestion performance. A total of 100 sludge samples were collected. The samples were characterised chemically and physically, and microbial groups were quantified by qRT-PCR. A chemical biological performance index strictly correlated to specific biogas production (rho=0.739, p<0.01) is proposed. This approach will produce new management tools for anaerobic digestion in wastewater treatment plants.

Responses of Macroinvertebrate Community Metrics to a Wastewater Discharge in the Upper Blue River of Kansas and Missouri, USA

The Blue River Main wastewater treatment facility (WWTF) discharges into the upper Blue River (725 km2), and is recently upgraded to implement biological nutrient removal. We measured biotic condition upstream and downstream of the discharge utilizing the macroinvertebrate protocol developed for Kansas streams. We examined responses of 34 metrics to determine the best indicators for discriminating site differences and for predicting biological condition. Significant differences between sites upstream and downstream of the discharge were identified for 15 metrics in April and 12 metrics in August. Upstream biotic condition scores were significantly greater than scores at both downstream sites in April (p = 0.02), and in August the most downstream site was classified as non-biologically supporting. Thirteen EPT taxa (Ephemeroptera, Plecoptera, Trichoptera) considered intolerant of degraded stream quality were absent at one or both downstream sites. Increases in tolerance metrics and filtering macroinvertebrates, and a decline in ratio of scrapers to filterers all indicated effects of increased nutrient enrichment. Stepwise regressions identified several significant models containing a suite of metrics with low redundancy (R2 = 0.90 - 0.99). Based on the rapid decline in biological condition downstream of the discharge, the level of nutrient removal resulting from the facility upgrade (10% - 20%) was not enough to mitigate negative effects on macroinvertebrate communities.

Illicit drug consumption estimated by wastewater analysis in different districts of Milan: A case study.

Wastewater analysis is a new approach developed to estimate illicit drug (ID) consumption in large communities, such as a city. We tested the ability of this approach to detect differences in consumption in different districts of a city. Consumption of cocaine, heroin, tetrahydrocannabinol (THC) (cannabis active principle), amphetamine, methamphetamine and ecstasy was estimated by analysis of selected drug excretion residues in composite 24 h samples of untreated urban wastewater by liquid chromatography-tandem mass spectrometry. Samples were collected from the inlet of the three main Milan wastewater treatment plants (WWTP), each serving a district of the city (west, center and east). In each WWTP, samples were taken daily for seven consecutive days in November 2010 and March 2011. We observed significant differences of ID consumption (expressed as mg/day/1000 inhabitants) among districts: consumption of some ID was significantly higher in the eastern district (P < 0.01 for THC, P < 0.001 for cocaine and P < 0.0001 for heroin by one-way analysis of variance), while consumption of methamphetamine and amphetamine was higher in the central area (P < 0.0001). Overall, from 2010 to 2011, ID consumption decreased in all the districts, in line with a recent population survey showing decreases from 25 to 55% in the annual prevalence of ID users in Italy. This approach may help to detect ID consumption in different districts of a city and may be useful for planning interventions aimed at specific city areas and substances.

Contributions and potential impacts of seven priority substances (As, Cd, Cu, Cr, Ni, Pb, and Zn) to a major European Estuary (Gironde Estuary, France) from urban wastewater

Urban wastewater metal inputs into coastal systems are of increasing interest to both scientists and managers facing restrictive environmental protection policies, population increase and changing metal applications. However, their impact and contribution to metal loads in estuarine and coastal environments is widely unknown due to the lack of (i) monitoring in both artificial and natural aquatic systems and (ii) an understanding of control parameters, such as spatial and temporal variations in hydrological conditions. We investigated the daily concentrations, fluxes and dynamics of seven EU priority contaminants (potentially toxic metals Cd, Cu, Cr, Ni, Pb, Zn and the metalloid As) transported by the Garonne River (La Réole site; watershed area ~57,000km2) to those released into the freshwater reaches of the Gironde Estuary (Garonne Branch) by two main wastewater treatment plants (WWTPs) of Bordeaux under low river discharge and contrasting rainfall situations. During short intense summer rainstorms, wastewater flow into the WWTPs increased by up to 150% and 60%, respectively, resulting in an increase of 70% (As) to 200% (Pb) for fluxes entering the treatment plants. Overall resulting WWTP particulate and dissolved effluent concentrations were up to 2 (Cr), 3 (Pb, Cu and Ni) and 5 (Cd and Zn) times higher than measured upstream in the Garonne River, respectively. During low-discharge, maximum outlet fluxes at the WWTPs were similar to respective watershed-derived fluxes in the Garonne River. During rain events, Pb in all fractions, total and dissolved Cu and total and particulate Zn fluxes entering the fluvial estuary were close to the respective minimum flux values at the La Réole site. Furthermore, during rain episodes, particulate Cu and dissolved Zn fluxes from the WWTPs to the fluvial estuary were greater than those transported by the Garonne River at the La Réole site. Mixing of treated wastewater with highly turbid estuarine freshwater most likely results in a re-equilibration between the dissolved and particulate phases, although biogeochemical processes in downstream estuarine turbidity and salinity gradients may partly reverse contaminant adsorption on estuarine particles. Accordingly, urban wastewater contaminant release clearly impacts estuarine water quality before being expulsed to the Bay of Biscay.

2D Electrical Resistivity Tomography Survey for Shallow Environmental Study at Wastewater Valley of Southwestern Erbil City, Iraqi Kurdistan Region

The use of wastewater for irrigation in sandy soil increases the pollution risk of the soil and may infiltrate to the water table of groundwater aquifer. This is happening in an area southwest of Erbil City on both sides of the main wastewater valley outlet. Characterizing and monitoring underground conditions and the location of subsurface contaminants is a challenging and costly endeavor. Many sensors and non-invasive geophysical measurement techniques have been developed to interpret the nature of the subsurface without disturbing it. In this study the Electrical Resistivity Tomography (ERT) was used to get detailed 2D resistivity models of the shallowest parts of the subsurface on both side of the valley along eight profiles. The wenner array was employed with 1m, 3m and 5m electrode spacing. The length of each profile was 60 m. To create a model for the subsurface resistivity Res2Dinv software was used. The results showed that the shallowest parts of the ground consist of two types of materials: the first is a clayey sandy gravel soil represents the recent alluvial deposits with resistivity value of 15-167 Ω.m and thickness 1-2 m. Many pollutant zones were detected within it; the second is saturated silty clay and other clayey materials with resistivity value of 9-52 Ω.m. Again some polluted zones were detected. Moreover some fractured areas were detected at where the risk of downward infiltration is expected. The resistivity value changes randomly in both horizontal and vertical direction because of the high infiltration which transports the contaminated materials downward and sideward along in homogeneities formed by human activity in the studied area.

Utilization of Waste from Para Rubber Industry to Produce Compost

A survey of cooperative concentrated rubber latex industry in southern Thailand showed that most of them do not have adequate treatments for their wastes. Especially, skim latex serum (SS) with high source of ammonia is a main wastewater generated from their industries and concentrated latex sludge (CS) with high source of phosphorus is a main solid waste obtained from their industries. It was noted that both of the wastes cause environment problems. Water pollution and bad smell of NH3from these waste systems have also been generated and affected to human health. One low investment possibility is the elaboration of these wastes by composting because these wastes contain some nutrients (N, P, K) in available forms resulting in high potential to add value for fertilizer production. However, both of the wastes have a small amount of organic matter content that need to be mixed with other materials with high organic matter such as sawdust (SD). Thus, the aim of this research was to investigate the utilization of these wastes to produce compost. In this work, the SS, CS and SD were composted in specially designed composting vessel (6L) with various mixing ratios of the SS, CS and SD in order to examine the optimized mixing condition and physical properties of the compost. Each treatment was composted with 60 days of composting duration. The performance of composting process was analyzed in term of the following: temperature, pH, electric conductivity, total organic carbon, total nitrogen, total phosphorus and C/N ratio. The analysis of temperature, pH, and electric conductivity was measured every day while the analysis of total organic carbon, total nitrogen, total phosphorus and C/N ratio was investigated every 10 days. According to the results, the optimized mixing ratio of SS, CS and SD for composting was 1:1:1. The final resultant compost was feasible for agricultural use. From the view point of compost qualities, it was in the range of the Thai compost standard with 7.91 of pH, 15.06 (%w/w) of total organic carbon, 1.24 (%w/w) of total nitrogen, 0.69 (%w/w) of total phosphorus and 21.6 of C/N ratio.

Integrated modeling of water quantity and quality in the Araguari River basin, Brazil

The Araguari River basin has a huge water resource potential. However, population and industrial growth have generated numerous private and collective conflicts of interest in the multiple uses of water, resulting in the need for integrated management of water quantity and quality at the basin scale. This study used the AQUATOOL Decision Support System. The water balance performed by the SIMGES module for the period of October 2006 to September 2011 provided a good representation of the reality of this basin. The parameters studied were dissolved oxygen, biochemical oxygen demand, organic nitrogen, ammonia, nitrate and total phosphorus. The coefficients of biochemical reactions, sedimentation rates and sediment dissolved oxygen release for this period were calibrated and validated in the quality modeling using the GESCAL module. A sensitivity analysis indicated that the coefficients of carbonaceous matter decomposition, nitrification, water temperature, and sediment oxygen demand interfered more significantly in the variables of state. To prevent eutrophication in the Nova Ponte reservoir and in the other cascade reservoirs, the local River Basin Committee should adopt restrictive actions against the use of agricultural fertilizers. On the other hand, in the sub basin of the Uberabinha River, new alternatives for public water supply to the city of Uberlândia and improvements in the treatment efficiency of the main wastewater treatment plant (WWTP) should be proposed, since the biochemical oxygen demand, ammonia and total phosphorus failed to meet the requirements of COPAM (2008) in the driest months.

PERSPECTIVES FOR ENERGETIC VALORIZATION OF WASTEWATER SEWAGE SLUDGE: THE TURIN CASE

The right individuation of the more convenient solution for final treatment and destination of sewage sludge deriving from wastewater plants, normally after anaerobic digestion process, is a very interesting problem, in accounting of urgent needs for acceptable solutions. The produced sludge, primarily after thermal drying, can be sent to energetic valorization processes as, for example, incineration, gasification and also pyrolysis. In this work we examined the thermal solutions (direct combustion in incineration plant first of all, but also gasification), for the sewage sludge deriving from the main Italian wastewater plants (ubicated in the metropolitan area of Turin), from both technological and environmental point of view. The plant actually produces about 100,000 t/y of sludge (38.9% d.s. (dry sludge)), in three main streams: centrifuged sludge, filtered sludge and thermal dried sludge. The water content of the streams is obviously different, while the indicated humidity is a mean value. In order to propose a solution for sludge valorization, a first analysis was carried out in order to define the main characteristics of the produced sludge (flow rates and composition); afterwards we analyzed in detail the potential plant design solutions, from the technological and the environmental point of view, achieving some perspectives in terms odd design data

Material selection for a constructed wetroof receiving pre-treated high strength domestic wastewater

A constructed wetroof (CWR) is defined in this study as the combination of a green roof and a constructed wetland: a shallow wastewater treatment system placed on the roof of a building. The foremost challenge of such CWRs, and the main aim of this investigation, is the selection of an appropriate matrix capable of assuring the required hydraulic retention time, the long-term stability and the roof load-bearing capacity. Six substrata were subjected to water dynamics and destructive tests in two testing-tables. Among all the materials tested, the substratum configuration composed of sand, light expanded clay aggregates, biodegradable polylactic acid beads together with stabilization plates and a turf mat is capable of retaining the water for approximately 3.8 days and of providing stability (stabilization plates) and an immediate protection (turf mat) to the system. Based on those results, a full-scale CWR was built, which did not show any physical deterioration after 1 year of operation. Preliminary wastewater treatment results on the full-scale CWR suggest that it can highly remove main wastewater pollutants (e.g. chemical oxygen demand, PO4(3-)-P and NH4(+)-N). The results of these tests and practical design considerations of the CWR are discussed in this paper.

Anaerobic digestion of stillage to produce bioenergy in the sugarcane-to-ethanol industry

Stillage is the main wastewater from ethanol production, containing a high chemical oxygen demand in addition to acidic and corrosive characteristics. Though stillage may be used as a soil fertilizer, its land application may be considered problematic due its high polluting potential. Anaerobic digestion represents an effective alternative treatment to reduce the pollution load of stillage. In addition, the methane gas produced within the process may be converted to energy, which can be directly applied to the treatment plant. The objective of this paper was to investigate the energetic potential of anaerobic digestion applied to stillage in the sugarcane ethanol industry. An overall analysis of the results indicates energy recovery capacity (ERC) values for methane ranging from 3.5% to 10%, respectively, for sugarcane juice and molasses. The processes employed to obtain the fermentable broth, as well as the distillation step, represent the main limiting factors to the energetic potential feasibility. Considering financial aspects the annual savings could reach up to US$ 30 million due to anaerobic digestion of stillage in relatively large-scale distilleries (365,000 m3 of ethanol per year). The best scenarios were verified for the association between anaerobic digestion of stillage and combustion of bagasse. In this case, the fossil fuels consumption in distilleries could be fully ceased, such the ERC of methane could reach values ranging from 140% to 890%.

Sensitive quantification of gadolinium-based magnetic resonance imaging contrast agents in surface waters using hydrophilic interaction liquid chromatography and inductively coupled plasma sector field mass spectrometry

The application of gadolinium(Gd)-based contrast agents to support medical examinations by magnetic resonance imaging (MRI) results in a large input of Gd into the environment. The long-term effects of the anthropogenic Gd anomaly, especially on aqueous ecosystems, are mostly unknown. The identification and quantification of Gd-based contrast agents in the aquatic environment requires the use of powerful methods of speciation analysis. Therefore, a method employing the hyphenation of hydrophilic interaction liquid chromatography (HILIC) and inductively coupled plasma sector field mass spectrometry (ICP-SFMS) with sample introduction as dry aerosol generated by desolvation was developed. The desolvation resulted in improved limits of detection for the predominantly used contrast agents well below 0.10nmol/L. This method was subsequently used for the analysis of Gd species in surface waters. Samples from a nature reserve in the city of Münster (Germany), into which the effluent from the city's main wastewater treatment plant enters the environment, were examined. The contrast agents Gd-DTPA, Gd-DOTA and Gd-BT-DO3A were identified and quantified in constant ratios in those samples. The concentrations were found in a range from 0.59nmol/L for Gd-DOTA up to 3.55nmol/L for Gd-BT-DO3A. As a result of mass balancing, the contrast agent concentration was found to account for 74–89% of total Gd concentrations, possibly indicating the presence of further Gd species. Nevertheless, there was no direct indication of species transformation by transmetallation reactions resulting in such Gd species. The determination of REE patterns by means of ICP-MS confirmed the results of speciation analysis showing significant Gd anomalies.

Management Efforts of Domestic Wastewater in Urban Based on Socio-Economic Variables

This paper presents the analysis of data related to domestic wastewater characteristics from area situated in Yogyakarta city of Sewon Wastewater Treatment Plant (WWTP). BOD load, which has not been used, is 416 kg/day (8.16%) in the ability of WWTP operational with the average rate of degradation for 1.85 day -1 and the retention time for 4.27 day and also the ability to degrade average organic materials for 86,54%. Simple regression models are presented for the prediction of basic wastewater characteristics, such as water consumption (l/person day), wastewater production (m 3 /day), Biochemical Oxygen Demand (BOD) load (l/person/day) and BOD concentration (mg/l). The models are based on simple socio- economic variables, with special attention to easily obtainable variable of total family income (number of minimum salaries earned per month). Most of the models are able to give an excellent prediction of the desired wastewater variables. Additionally, behavior of the main wastewater characteristics according to the day is analyzed used to variation data period 1.5 years. Based on the results obtained, it is suggested that the classical figures of BOD concentration of 413.69 mg/l and per capita BOD load 96.69 l/person/day do apply to typical population predominant in Yogyakarta city. The actual BOD data concentration are frequently lower than 300 mg/l, while the BOD load is frequently lower than 96 l/person/day. Sewon IPAL is eficient enough in dealing with the process of wastewater treatment. The result obtained can be used for design purposes in the area studied, and possibly in areas of similar characteristics.

Photocatalysis as a potential tertiary treatment of urban wastewater: new photocatalytic materials

Heterogeneous UV-photocatalytic process has been studied as tertiary treatment of real municipal wastewater. Wastewater photocatalytic treatment was carried out using several materials previously developed as photocatalysts: volcanic ashes and nanostructured titania supported over volcanic ashes. Both material activities in particles were compared with Degussa TiO2 (powder). Photocatalyst amount influence was studied by varying it between 2 and 10 g L−1. Wastewater decontamination process was evaluated measuring the chemical oxygen demand evolution with phototreatment time in order to choose the best photocatalytic material and its optimal operation concentration. Moreover, the photocatalytic results obtained were compared with those obtained from photolysis and adsorption studies in wastewater using the same operation conditions. In addition, analyses of main wastewater parameters were made in order to evaluate the complete water decontamination process. Possibility of using photocatalysts in particles shows the main advantage of continuous photocatalyst separation from the water effluent once the decontamination process has finished. Good photocatalytic activities were observed, and it allows to conclude that heterogeneous photocatalysis is an effective method for municipal wastewater treatment, achieving water disinfection and phosphates removal.

Pilot Study of the Estimation of Amphetamines Consumption in the Polish City of Poznan

According to the European Monitoring Centre for Drugs and Drug Addiction Annual Report 2011 in many European countries amphetamines or ecstasy is the second most commonly used illicit substance after cannabis. More reliable and objective method based on the ‘sewage epidemiology’ was applied to estimate the level of amphetamines consumption in Poland. Amphetamine, methamphetamine and MDMA (ecstasy) were determined in wastewater samples collected from the main Wastewater Treatment Plant in the Polish city of Poznan (about 687,000 people) using liquid chromatography/tandem mass spectrometry (LC-MS-MS). Back-calculations used in the ‘sewage epidemiology’ approach were applied to estimate the level of consumption of analyzed drugs. Analysis of variance (ANOVA) was applied to check the monthly differences between determinations. Two-year profiles of consumption for amphetamine methamphetamine and ecstasy were calculated. Results from our city indicate that consumption of amphetamines is one order of magnitude lower than in Western Europe. Therefore, there is a different profile of amphetamines consumption. Consumption of amphetamine is several times lower, but the consumption of ecstasy is relatively high. ANOVA analysis confirmed significant differences between monthly loads of determined illicit drugs